162 Mr. W. Murton Holmes on the 



like leaves, within which are cavities penetrable by minute 

 animals only, on account of the narrowness of the entry. The 

 animals are retained and drained of their juices by means of 

 protoplasmic filaments radiating from special cells. One of 

 these is the toothwort, a plant nearly allied to the yellow rattle, 

 but is destitute of chlorophyll, and lives underground parasitic 

 on the roots of trees and shrubs. The toothwort has not the 

 power of converting atmospheric carbonic acid, or crude food-sap 

 absorbed by its suckers from the plants to which it is attached, 

 into the various organic compounds necessary for further growth. 

 For this reason, and inasmuch as the quantity of nitrogenous 

 compounds in the fluids withdrawn from the roots is but small, 

 every additional supply of organic food, especially of nitrogenous 

 matter such as is derived from captured animals, must be ex- 

 ceedingly welcome. 



Some carnivorous plants perform movements for the capture of 

 their prey. To this class belongs the butterwort. The flowers 

 are borne singly on slender stalks arising from the centre of a 

 rosette of leaves that rest upon the ground. The leaves are 

 oblong, and, owing to the lateral margins being somewhat up- 

 turned, are converted into a broad flat-bottomed trough, which 

 is covered with a colourless sticky mucilage secreted by glands 

 distributed in large numbers over the entire upper surface. As 

 soon as a nitrogenous organic body, such as white of egg, clotted 

 blood, milk, &c., is brought into continuous contact with the 

 glands, they are forthwith stimulated, not only to a more profuse 

 elimination of mucilage, but also to the secretion of an acid 

 liquid which has the power of dissolving all bodies of this kind. 

 An insect alighting on the leaf is held fast by the mucilage, and 

 the edges of the leaf curl over so as to cover it, and bring it into 

 contact with as many glands as possible. This involution takes 

 place very slowly, it being usually some hours before the insect 

 is enfolded. Alter solution and absorption are accomplished, 

 usually at the end of six hours, the leaf expands again, and 

 its margins resume their original position. Spores and 

 pollen-grains falling upon the leaf are subjected to the same 

 fate as insects. The action of the acid liquid, which is a case 

 of true digestion, is identical with that of the gastric juice of 

 animals. 



In the sundew the movements whereby the capture and 

 digestion of small animals is effected occur much more rapidly 

 and obviously. The leaves are covered with a number of club- 

 shaped hairs, surmounted by a glistening drop of a sticky fluid, 

 whose function is essentially the same as that of the glands of the 

 butterwort. The insects that fly on to the leaves and are caught 

 by the sticky liquid try to disencumber themselves by stroking 

 the viscous matter off with their legs, only to besmear themselves 



